In vehicular transmissions, such as but not limited to a dual clutch transmission and an automatic manual transmission, synchronizers are used to engage the different gears to achieve the different gear ratios. The synchronizer includes a synchronizer hub fixedly mounted to a shaft of the transmission, a slidable sleeve meshingly engaged with the hub, and a blocker ring mounted on the shaft between the hub and the gear to be engaged. During a synchronization event, the sleeve is moved by an actuator fork that slides the sleeve axially relative to the shaft axis across the blocker ring and into interlocking engagement with a gear. The synchronization event includes a pre-synchronization phase followed by a synchronization phase. The timing, position and movement of the actuator forks must be precisely controlled to control the timing, position and movement of the sleeve attached thereto during the synchronization event to obtain consistent, smooth shifts.
The actuator forks may be controlled, for example, by a pressure solenoid that applies a fluid pressure to a first side of an actuator piston, and a flow solenoid disposed in series with the pressure solenoid and controlling fluid flow from a second side of the actuator piston. Movement of the actuator piston moves the actuator fork. The magnitude of the fluid pressure applied to the first side of the actuator piston determines how fast the actuator piston moves, and thereby how fast the actuator fork moves. An increase in the fluid pressure applied to the first side of the actuator piston increases the velocity at which the actuator fork moves, thereby decreasing the time elapsed during movement of the actuator fork from an initial disengaged position through the pre-synchronization phase and through the synchronization phase to a target engaged position. In contrast, a decrease in the fluid pressure applied to the first side of the actuator piston decreases the velocity at which the actuator fork moves, thereby decreasing the time elapsed during movement of the actuator fork from an initial disengaged position through the pre-synchronization phase and through the synchronization phase to an engaged target position.